The present invention relates to an air flow rate meter apparatus including at least one temperature-dependent resistor whose temperature and/or resistance is regulated in accordance with the mass of flowing air and whose control variable represents a standard for the flowing air mass. An air flow conduit having a restriction is provided into which an air bypass line discharges. A mass of air flows through the air bypass line at a rate proportional to the mass of air flowing through the air flow conduit. An air flow rate meter, which includes the temperature-dependent resistor, is disposed in the air bypass line.
An air flow rate meter apparatus is already known in which the temperature-dependent resistor disposed in the air bypass line is brought to glow heat from time to time by means of an increased flow of electrical current, in order to burn off desirable deposits on the surface of the temperature-dependent resistor. In using such an air flow rate meter apparatus at the air intake tube of an internal combustion engine, a disadvantage exists in that during this burnoff process, because of the increase in the gases of combustion and the heated air from the air intake tube, a fuel-air mixture is aspirated which ignites at the glowing hot temperature-dependent resistor and causes an undesirable further increase in temperature at the temperature-dependent resistor. The result is not only the danger of fire but further glowing of the temperature-dependent resistor even after the burnoff process has ended, causing destruction of the temperature-dependent resistor.